Investigation of subglacial weathering under the Greenland Ice Sheet using silicon isotopes
Subglacial chemical weathering plays a key role in global silicate weathering budgets, contributing to the cycling of silicon (Si) in terrestrial and marine systems and the potential drawdown of carbon dioxide from the atmosphere. Here, we use data from two Greenland Ice Sheet (GrIS) catchments to d...
Published in: | Geochimica et Cosmochimica Acta |
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Format: | Article in Journal/Newspaper |
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Online Access: | https://orca.cardiff.ac.uk/id/eprint/127083/ https://doi.org/10.1016/j.gca.2018.12.033 https://orca.cardiff.ac.uk/id/eprint/127083/1/hatton-et-al-2019-1.pdf |
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ftunivcardiff:oai:https://orca.cardiff.ac.uk:127083 2023-05-15T16:21:30+02:00 Investigation of subglacial weathering under the Greenland Ice Sheet using silicon isotopes Hatton, J. E. Hendry, K. R. Hawkings, J. R. Wadham, J. L. Kohler, T. J. Stibal, M. Beaton, A. D. Bagshaw, E. A. Telling, J. 2019-02-15 application/pdf https://orca.cardiff.ac.uk/id/eprint/127083/ https://doi.org/10.1016/j.gca.2018.12.033 https://orca.cardiff.ac.uk/id/eprint/127083/1/hatton-et-al-2019-1.pdf en eng Elsevier https://orca.cardiff.ac.uk/id/eprint/127083/1/hatton-et-al-2019-1.pdf Hatton, J. E., Hendry, K. R., Hawkings, J. R., Wadham, J. L., Kohler, T. J., Stibal, M., Beaton, A. D., Bagshaw, E. A. https://orca.cardiff.ac.uk/view/cardiffauthors/A1991811U.html orcid:0000-0001-8392-1750 orcid:0000-0001-8392-1750 and Telling, J. 2019. Investigation of subglacial weathering under the Greenland Ice Sheet using silicon isotopes. Geochimica et Cosmochimica Acta 247 , pp. 191-206. 10.1016/j.gca.2018.12.033 https://doi.org/10.1016/j.gca.2018.12.033 file https://orca.cardiff.ac.uk/id/eprint/127083/1/hatton-et-al-2019-1.pdf doi:10.1016/j.gca.2018.12.033 cc_by_nc_nd CC-BY-NC-ND Article PeerReviewed 2019 ftunivcardiff https://doi.org/10.1016/j.gca.2018.12.033 2022-10-27T22:48:52Z Subglacial chemical weathering plays a key role in global silicate weathering budgets, contributing to the cycling of silicon (Si) in terrestrial and marine systems and the potential drawdown of carbon dioxide from the atmosphere. Here, we use data from two Greenland Ice Sheet (GrIS) catchments to demonstrate how Si isotopes from dissolved and amorphous particulate fractions (δ30DSi and δ30ASi respectively) can be used together with major ion data to assess the degree of secondary silicate weathering product formation and redissolution in subglacial environments. We compare a time-series of summer melt seasons from the two study sites, which differ in catchment size (∼600 km2 for Leverett Glacier (LG) and ∼36 km2 for Kiattuut Sermiat (KS)). Subglacial waters from LG have elevated Na+ and K+ ions in relation to Ca2+ and Mg2+ ions, indicating a predominance of silicate weathering, whilst meltwaters from KS are characterised by carbonate weathering (hydrolysis and carbonation) throughout the melt season. Both catchments have mean δ30DSi values substantially lower than average riverine values (KS 0.41‰, LG −0.25‰, versus a global riverine mean of 1.25‰) and display a seasonal decline, which is more pronounced at LG. The δ30ASi values (discharge weighted mean values KS −0.44‰, LG −0.22‰) are lighter than the bedrock (mean values KS −0.18 ± 0.12‰, LG 0.00 ± 0.07‰) in both catchments, indicating a secondary weathering product origin or leaching of lighter isotopes during initial weathering of crushed rock. When used in combination, the major ion and silicon isotope data reveal that the extent of silicate weathering and secondary phase redissolution are more pronounced at LG compared to KS. Contrasting weathering regimes and subglacial hydrology between catchments need to be considered when estimating the δ30Si composition of silica exported into polar oceans from the GrIS, with larger catchments likely to produce fluxes of lighter δ30Si. As larger catchments dominate freshwater export to the ocean, GrIS meltwater is ... Article in Journal/Newspaper glacier Greenland Ice Sheet Leverett Glacier Cardiff University: ORCA (Online Research @ Cardiff) Greenland Kiattuut Sermiat ENVELOPE(-45.267,-45.267,61.267,61.267) Leverett Glacier ENVELOPE(-147.583,-147.583,-85.633,-85.633) Geochimica et Cosmochimica Acta 247 191 206 |
institution |
Open Polar |
collection |
Cardiff University: ORCA (Online Research @ Cardiff) |
op_collection_id |
ftunivcardiff |
language |
English |
description |
Subglacial chemical weathering plays a key role in global silicate weathering budgets, contributing to the cycling of silicon (Si) in terrestrial and marine systems and the potential drawdown of carbon dioxide from the atmosphere. Here, we use data from two Greenland Ice Sheet (GrIS) catchments to demonstrate how Si isotopes from dissolved and amorphous particulate fractions (δ30DSi and δ30ASi respectively) can be used together with major ion data to assess the degree of secondary silicate weathering product formation and redissolution in subglacial environments. We compare a time-series of summer melt seasons from the two study sites, which differ in catchment size (∼600 km2 for Leverett Glacier (LG) and ∼36 km2 for Kiattuut Sermiat (KS)). Subglacial waters from LG have elevated Na+ and K+ ions in relation to Ca2+ and Mg2+ ions, indicating a predominance of silicate weathering, whilst meltwaters from KS are characterised by carbonate weathering (hydrolysis and carbonation) throughout the melt season. Both catchments have mean δ30DSi values substantially lower than average riverine values (KS 0.41‰, LG −0.25‰, versus a global riverine mean of 1.25‰) and display a seasonal decline, which is more pronounced at LG. The δ30ASi values (discharge weighted mean values KS −0.44‰, LG −0.22‰) are lighter than the bedrock (mean values KS −0.18 ± 0.12‰, LG 0.00 ± 0.07‰) in both catchments, indicating a secondary weathering product origin or leaching of lighter isotopes during initial weathering of crushed rock. When used in combination, the major ion and silicon isotope data reveal that the extent of silicate weathering and secondary phase redissolution are more pronounced at LG compared to KS. Contrasting weathering regimes and subglacial hydrology between catchments need to be considered when estimating the δ30Si composition of silica exported into polar oceans from the GrIS, with larger catchments likely to produce fluxes of lighter δ30Si. As larger catchments dominate freshwater export to the ocean, GrIS meltwater is ... |
format |
Article in Journal/Newspaper |
author |
Hatton, J. E. Hendry, K. R. Hawkings, J. R. Wadham, J. L. Kohler, T. J. Stibal, M. Beaton, A. D. Bagshaw, E. A. Telling, J. |
spellingShingle |
Hatton, J. E. Hendry, K. R. Hawkings, J. R. Wadham, J. L. Kohler, T. J. Stibal, M. Beaton, A. D. Bagshaw, E. A. Telling, J. Investigation of subglacial weathering under the Greenland Ice Sheet using silicon isotopes |
author_facet |
Hatton, J. E. Hendry, K. R. Hawkings, J. R. Wadham, J. L. Kohler, T. J. Stibal, M. Beaton, A. D. Bagshaw, E. A. Telling, J. |
author_sort |
Hatton, J. E. |
title |
Investigation of subglacial weathering under the Greenland Ice Sheet using silicon isotopes |
title_short |
Investigation of subglacial weathering under the Greenland Ice Sheet using silicon isotopes |
title_full |
Investigation of subglacial weathering under the Greenland Ice Sheet using silicon isotopes |
title_fullStr |
Investigation of subglacial weathering under the Greenland Ice Sheet using silicon isotopes |
title_full_unstemmed |
Investigation of subglacial weathering under the Greenland Ice Sheet using silicon isotopes |
title_sort |
investigation of subglacial weathering under the greenland ice sheet using silicon isotopes |
publisher |
Elsevier |
publishDate |
2019 |
url |
https://orca.cardiff.ac.uk/id/eprint/127083/ https://doi.org/10.1016/j.gca.2018.12.033 https://orca.cardiff.ac.uk/id/eprint/127083/1/hatton-et-al-2019-1.pdf |
long_lat |
ENVELOPE(-45.267,-45.267,61.267,61.267) ENVELOPE(-147.583,-147.583,-85.633,-85.633) |
geographic |
Greenland Kiattuut Sermiat Leverett Glacier |
geographic_facet |
Greenland Kiattuut Sermiat Leverett Glacier |
genre |
glacier Greenland Ice Sheet Leverett Glacier |
genre_facet |
glacier Greenland Ice Sheet Leverett Glacier |
op_relation |
https://orca.cardiff.ac.uk/id/eprint/127083/1/hatton-et-al-2019-1.pdf Hatton, J. E., Hendry, K. R., Hawkings, J. R., Wadham, J. L., Kohler, T. J., Stibal, M., Beaton, A. D., Bagshaw, E. A. https://orca.cardiff.ac.uk/view/cardiffauthors/A1991811U.html orcid:0000-0001-8392-1750 orcid:0000-0001-8392-1750 and Telling, J. 2019. Investigation of subglacial weathering under the Greenland Ice Sheet using silicon isotopes. Geochimica et Cosmochimica Acta 247 , pp. 191-206. 10.1016/j.gca.2018.12.033 https://doi.org/10.1016/j.gca.2018.12.033 file https://orca.cardiff.ac.uk/id/eprint/127083/1/hatton-et-al-2019-1.pdf doi:10.1016/j.gca.2018.12.033 |
op_rights |
cc_by_nc_nd |
op_rightsnorm |
CC-BY-NC-ND |
op_doi |
https://doi.org/10.1016/j.gca.2018.12.033 |
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Geochimica et Cosmochimica Acta |
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247 |
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191 |
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1766009507828203520 |